With Windows 8 we get WinRT, the win32 replacement that treats XAML/.NET and HTML5/JS equally, *for desktop apps*. I emphasise the last point, because MS have pretty much given us nothing with respect to Web Apps, except the obvious conclusion that the promotion of HTML5 means MS want us to focus on that.
However, all of the tools that MS has given developers for HTML5 center around Metro desktop applications, and there is very little reuse that can be applied between the Metro HTML5 experience and normal web HTML5 development since everything is tied in so closely with the WinJS libraries. Conversely Silverlight and WPF share many of the controls and libraries and development for both environments is very similar, so windows developers who currently have the full stack of web (silverlight) and desktop (WPF) knowledge will now have to stick to doesktop only (xaml) or learn HTML5 for Web and either HTML5/WinRT or XAML for desktop.
Unless some love is given to Silverlight, Devs are going to have to learn HTML5/JS for web applications, and therefore why not learn HTML5/JS for WinRT at the same time, so what's the point of .NET? There's some hyperbole for you, but I'm sure there are a lot of .NET Devs thinking that very thing.
And the crux is, .Net development is so good because you can be so productive with the tools at your disposal, and XAML development is no exception. HTML5/JS development is far less productive, and far more painful for developers, so for .Net developers moving to HTML5/JS development, there is going to be regression in the productivity and quality of work, which benefits no one.